Keyhole-guard



No. 606,734. I Patented July 5, I898.

F. E. OLMSTEAD.

KEYHOLE GUARD.

(Application filed June 1, 1897.)

(No Model.)

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. UNITEDQSTATE PATENT ()FFICE,

FREEMAN E. OLMSTEAD, OF DENVER, COLORADO.

' KEYHOLE-GUARD.

SPECIFICATION forming part of Letters Patent No. 606,734, dated July 5, 1898.

Application filed June 1, 1897. Serial No. 639,000. (No model.) I

To all whom it may concern:

Beit known that I, FREEMAN E. OLMSTEAD, a citizen of the United'States of America, residing at Denver, in the county of Arapahoe and State of Colorado, have invented certain new and useful Improvements in Keyhole- Guards; and I do declare the following to be a full, clear, andexact description of the in vention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had tothe accompanying drawings, and to the figures of refer ence marked thereon, which form a part of this specification.

My invention relates to improvements in keyhole-guards, my object being to close the keyhole of the door to prevent the insertion of a key from the outside by a person evilly disposed or unauthorized 'so to do.

My improved deviceis adapted for use with doors equipped with common locks having keys consisting of stems circular in cross-section and having fiat blades or projections in which are formed Wards adapted to fit the lock mechanism. It is well known that locks of this character are very insecure and quite easily picked or unlocked. As before stated, my improvement is for the purpose of protecting locks of this class; and to this end it consists of the features hereinafter described and claimed, all of which will be fully understood by reference to the accompanying drawings,in which is illustrated an embodiment thereof.

In the drawings, Figure 1 shows a section taken through a door equipped with my improved device. Fig. 2 is a view of the door from the inside. Fig. 3 is aperspective View of the device shown in detail.

Similar reference characters indicating corresponding parts in the views, let the numeral 5 designate the body of the device, consisting of a small lock-casing in which is inserted a stem 6, having a projectionfi, formed at its outer extremity and extending atright angles to the stem. This stem and its pro jection are adapted to enter the keyhole 7 and pass entirelythrough the door. When the device is thus applied, the projection 6 protrudes from the keyhole on the inside of the door. When first inserted, the device is in the position shown in dotted lines in Fig. 1. It is then given a half-turn, causing it to occupy the position shown in full lines in Fig. 1, in which case the projection 6 extends above the top of the keyhole and'forms'a stop against the withdrawal of the device from the door until it is again turned to the position of original insertion.

To prevent the turning of the device after it is applied to the door, the casing 5 is equipped with suitable lock mechanism having a bolt 9 adapted to be thrown into the keyhole, (see Fig. 1,) said bolt being of such shape and dimensions'as to prevent the turning of the device whenthe said bolt is in this position. The lock mechanism of the device may be as complicated as desired. It should be a look not easily picked or opened, except bya person holding the key. As shown in the drawings, the casing 5 is equipped with a cylinder-lock having a fiat key. The stem 6 and its projection 6 are so shaped as to enter and pass through any ordinary keyhole of the character described' The stem 6 is screwed into the casing 5, whereby its length may be extended or adjusted to fit doors of varying thickness. To the threaded portion of the stem is applied a lock-nut 10,Which is screwed down against the casing when the stem is properly adjusted. This nut prevents the stem from turning in the casing when the device is in use.

Before inserting the stem 6 in the keyhole the stem is turned in the threaded opening in the case 5 until its'protruding portion is of a length corresponding with the thickness of the door and so adjusted that the parts 5 and 6 occupy the relative positions shown in Figs.

l and 3. The lock-nut 10 is then screwed tightly against the case, whereby the stem is ing this last-named door he removes thekey and inserts the stem 6 of the device until the part 6 protrudes fromthe" keyhole on the inside'of the door, the length of thesame having been properly adj ustedto accomplishthis The device is then in the position purpose.

shown in dotted lines in Fig. 1. It is then turned while the stem is in the keyhole to the position shown in full lines in Fig. 1, thus causing the part (3 of the stem to form a stop against the withdrawal of the stem from the keyhole. The key 9 is then inserted in the look of the casing 5 and turned to throw the bolt 9 into the keyhole, thus preventing the turning of the device until the bolt is withdrawn from the keyhole.

It will thus be seen that this device ait'ords an efiicient guard against access to the keyholes of outside doors.

Having thus described my invention, what I claim is In a keyhole-guard, the combination of a look, a stem adjustable thereon, means for securing the stem. rigidly on the loekease, the said stem having a projection at its free extremity adapted when the stem is properly turned in the keyhole to prevent its withdrawal, the lock being provided with a movable bolt adapted to enter the keyhole and prevent the turning of the stem, the parts being so arranged that when the projection on the stem is adapted to enter the keyhole, the bolt of the lock is out of line therewith, but when the bolt is in line with the keyhole, the said projection is out of line therewith, and suitable means for actuating the said belt for the purpose set forth.

In testimony whereof I al'lix my signature in presence of two witnesses.

FREEMAN E. OLMCTEAD.

\Vitnesses:

ISIIAM R. IIoWzE, A. J. OBRIEN. 

